JP7116710B2 - pneumatic tire - Google Patents

Description

The present invention relates to pneumatic tires.

As a technique for improving the drainage performance of a tire when wear progresses, it has been proposed to provide a groove whose groove width increases when wear progresses on the tread surface of the tire (for example, Patent Document 1).

Japanese Patent Publication No. 2013-540077

However, with the technique described in Patent Document 1, when a portion where the groove width becomes large appears as the wear progresses, the rigidity of such a portion becomes low, causing local wear, which may cause uneven wear of the tire. was there.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a pneumatic tire that can improve drainage performance while suppressing the occurrence of uneven wear when wear progresses.

The gist and configuration of the present invention are as follows.
(1) Between a plurality of circumferential main grooves extending in the tread circumferential direction and the circumferential main grooves adjacent in the tread width direction among the plurality of circumferential main grooves on the tread surface, or in the circumferential direction A pneumatic tire having a plurality of land portions partitioned by main grooves and tread edges,
The land portion has a plurality of width direction grooves extending in the tread width direction,
The width direction groove has, on the groove bottom side, a widened portion in which the groove width is larger than that on the tread surface side,
When the pneumatic tire is mounted on an applicable rim, filled with a specified internal pressure, and in an unloaded state, the groove width of the widened portion of the width direction groove is 2.5 times or more the opening width of the tread surface. When the groove depth position on the outermost side in the tire radial direction is set as the reference depth position,
In a tire radial direction region including at least the reference depth position, the storage elastic modulus of the first tread rubber, which is a groove wall surface layer portion that is partitioned by the widened portion and covers at least a part of the widened portion, is equal to the first greater than the storage modulus of the second tread rubber in the region surrounding the tread rubber of the second pneumatic tire.
According to this, it is possible to improve the drainage performance while suppressing the occurrence of uneven wear when the wear progresses.

(2) Between a plurality of circumferential main grooves extending in the tread circumferential direction and the circumferential main grooves adjacent in the tread width direction among the plurality of circumferential main grooves on the tread surface, or in the circumferential direction A pneumatic tire having a plurality of land portions partitioned by main grooves and tread edges,
The land portion has a plurality of width direction sipes extending in the tread width direction,
The width direction sipe has, on the sipe bottom side, a widened portion in which the sipe width is larger than the tread tread surface side,
When the pneumatic tire is mounted on an applicable rim, filled with a specified internal pressure, and in a no-load state, the sipe width of the widened portion of the width direction sipe is 2.5 times or more the opening width of the tread surface. When the sipe depth at the outermost tire radial direction is defined as the reference depth position,
In a tire radial direction region including at least the reference depth position, the storage elastic modulus of the first tread rubber, which is a groove wall surface layer portion that is partitioned by the widened portion and covers at least a part of the widened portion, is equal to the first greater than the storage modulus of the second tread rubber in the region surrounding the tread rubber of the second pneumatic tire.
This also makes it possible to improve the drainage performance while suppressing the occurrence of uneven wear when the wear progresses.

(3) Between a plurality of circumferential main grooves extending in the tread circumferential direction and the circumferential main grooves adjacent in the tread width direction among the plurality of circumferential main grooves on the tread surface, or in the circumferential direction A pneumatic tire having a plurality of land portions partitioned by main grooves and tread edges,
The land portion has one or more circumferential sipes extending in the tread circumferential direction,
The circumferential sipe has, on the sipe bottom side, a widened portion where the sipe width is larger than the tread surface side,
The sipe width of the widened portion of the circumferential sipe is 2.5 times or more the opening width of the tread surface when the pneumatic tire is mounted on an applicable rim, filled with a specified internal pressure, and in a no-load state. When the sipe depth at the outermost tire radial direction is defined as the reference depth position,
In a tire radial direction region including at least the reference depth position, the storage elastic modulus of the first tread rubber, which is a groove wall surface layer portion that is partitioned by the widened portion and covers at least a part of the widened portion, is equal to the first greater than the storage modulus of the second tread rubber in the region surrounding the tread rubber of the second pneumatic tire.
This also makes it possible to improve the drainage performance while suppressing the occurrence of uneven wear when the wear progresses.

Here, "tread tread surface" refers to the entire tread surface in the circumferential direction of the tread, which comes into contact with the road surface when the pneumatic tire is mounted on the applicable rim, filled with the specified internal pressure, and the maximum load is applied. refers to the aspect of
In addition, the "circumferential direction main groove" extends in the tread circumferential direction, and when a pneumatic tire is mounted on an applicable rim, filled with a specified internal pressure, and no load is applied, the width of the opening at the tread surface is 1. .5mm or more.
Further, the term "tread edge" refers to the outermost points on both sides of the tread surface in the tire width direction.
Further, the "width direction groove" means that the width of the opening on the tread surface extends in the tread width direction, and the pneumatic tire is mounted on the applicable rim, filled with the specified internal pressure, and no load is applied. 0 mm or more.
In addition, the "width direction sipe" extends in the tread width direction, and when a pneumatic tire is mounted on an applicable rim, filled with a specified internal pressure, and no load is applied, the width of the opening on the tread surface is 1. It means less than 0mm.
The term "circumferential sipe" means that the width of the opening on the tread surface when the pneumatic tire extends in the tread circumferential direction, is mounted on an applicable rim, is filled with a specified internal pressure, and is not loaded, is 1. Anything less than 5 mm.
In addition, "storage elastic modulus" refers to the one measured at a temperature of 25°C in accordance with JIS K7244.

As used herein, the term "applicable rim" refers to an industrial standard valid in the region where the tire is produced and used, such as JATMA (Japan Automobile Tire Manufacturers Association) JATMA YEAR BOOK in Japan and ETRTO (The European Standard) in Europe. Standard rims (ETRTO's STANDARDS MANUAL) in application sizes, which are described in the STANDARDS MANUAL of the Tire and Rim Technical Organization, and in the YEAR BOOK of the TRA (The Tire and Rim Association, Inc.) in the United States or will be described in the future Measuring Rim in TRA, Design Rim in TRA's YEAR BOOK) (that is, the above "rim" includes sizes that may be included in the above industrial standards in the future in addition to current sizes. An example of the "size" is the size listed as "FUTURE DEVELOPMENTS" in the ETRTO 2013 edition.) However, if the size is not listed in the above industrial standards, it corresponds to the bead width of the tire. A rim with a wider width.
In addition, "specified internal pressure" refers to the air pressure (maximum air pressure) corresponding to the maximum load capacity of a single wheel in the applicable size and ply rating described in JATMA, etc., and for sizes not described in the above industrial standards. In this case, the "specified internal pressure" refers to the air pressure (maximum air pressure) corresponding to the maximum load capacity specified for each vehicle on which the tire is mounted.
Also, the term "maximum load" refers to the load corresponding to the maximum load capacity.

(4) In any one of (1) to (3) above, the width at the reference depth position is not the maximum width, and the tire radial direction area is at least in the tire radial direction from the reference depth position to: It is preferable that the widened portion includes a region up to a position in the tire radial direction where the width becomes maximum.
According to this configuration, it is possible to further suppress the occurrence of uneven wear and improve the drainage performance when the wear progresses.
In addition, when the "tire radial position at which the maximum width is achieved" has a width in the tire radial direction, it means the outermost position in the tire radial direction of the region.

(5) In any one of (1) to (4) above, it is preferable that the tire radial region is the entire area from the tire radially innermost end to the tire radially outermost end of the widened portion.
According to this configuration, it is possible to improve drainage while further suppressing the occurrence of uneven wear when wear progresses.

(6) In the above (1) or the above (4) or (5) in the above (1), the outline of the widened portion of the width direction groove of the first tread rubber in the tread circumferential cross-sectional view. The thickness t in the normal direction is preferably 1.0 mm or more.
By setting the content within the above range, it is possible to further suppress the occurrence of uneven wear and improve the drainage property when the wear progresses.
In addition, "thickness t" shall mean the maximum thickness when the thickness is not constant.

(7) In (2) or (4) or (5) in (2) above, the outline of the widened portion of the widthwise sipe of the first tread rubber in the tread circumferential cross-sectional view. The thickness t in the normal direction is preferably 1.0 mm or more.
By setting the content within the above range, it is possible to further suppress the occurrence of uneven wear and improve the drainage property when the wear progresses.

(8) In (3) or (4) or (5) in (3) above, the outline of the widened portion of the circumferential sipe of the first tread rubber in the tread circumferential cross-sectional view. The thickness t in the normal direction is preferably 1.0 mm or more.
By setting the content within the above range, it is possible to further suppress the occurrence of uneven wear and improve the drainage property when the wear progresses.

(9) In any one of (1) to (8) above, the storage elastic modulus of the first tread rubber is preferably 1.5 times or more the storage elastic modulus of the second tread rubber.
By setting it within the above range, it is possible to improve the drainage property while suppressing the occurrence of uneven wear particularly when the wear progresses.

(10) In any one of (1) to (9) above, the storage elastic modulus of the first tread rubber is preferably 1.8 times or more the storage elastic modulus of the second tread rubber.
By setting it within the above range, it is possible to improve the drainage performance while further suppressing the occurrence of uneven wear when the wear progresses.

(11) In (1) or (4) to (6), (9), and (10) in (1) above, the land portion defined by at least the tread edge has the widened portion in the width direction. It is preferred to have grooves.
According to this configuration, it is possible to improve drainage performance while suppressing the occurrence of uneven wear when wear progresses, particularly in at least the land portion defined by the tread edge.

(12) In (2) or (4), (5), (7), (9), and (10) in (2) above, the widened portion is provided in at least the land portion defined by the tread edge. It is preferable to have the width direction groove having
According to this configuration, it is possible to improve drainage performance while suppressing the occurrence of uneven wear when wear progresses, particularly in at least the land portion defined by the tread edge.

(13) In (3) or (4), (5), (8) to (10) in (3) above, the land portion defined by at least the tread edge has the widened portion in the width direction. It is preferred to have grooves.
According to this configuration, it is possible to improve drainage performance while suppressing the occurrence of uneven wear when wear progresses, particularly in at least the land portion defined by the tread edge.

ADVANTAGE OF THE INVENTION According to this invention, the pneumatic tire which can improve drainage property can be provided, suppressing occurrence of uneven wear at the time of progress of wear.

1 is a development view schematically showing a tread pattern of a pneumatic tire according to one embodiment of the present invention; FIG. FIG. 4 is a cross-sectional view schematically showing an example of width direction grooves; FIG. 5 is a development view schematically showing a tread pattern of a pneumatic tire according to another embodiment of the invention; It is a sectional view showing an example of width direction Sipe typically. FIG. 4 is a development view schematically showing a tread pattern of a pneumatic tire according to another embodiment of the invention; It is a sectional view showing an example of a peripheral direction Sipe typically.

Embodiments of the present invention will be exemplified in detail below with reference to the drawings.
Here, the internal structure and the like of the pneumatic tire (hereinafter also simply referred to as a tire) can have the same structure as the conventional one. As an example, the tire may have a pair of bead portions, a pair of sidewall portions connected to the pair of bead portions, and a tread portion disposed between the pair of sidewall portions. . Further, the tire may have a carcass that straddles a pair of bead portions in a toroidal shape, and a belt that is arranged outside the crown portion of the carcass in the tire radial direction.
Hereinafter, unless otherwise specified, the dimensions, etc. refer to the dimensions, etc., when the tire is mounted on an applicable rim, filled with a specified internal pressure, and placed in an unloaded state.

FIG. 1 is a developed view schematically showing a tread pattern of a pneumatic tire according to one embodiment of the present invention.

As shown in FIG. 1, the tire of this example has a tread surface 1, a plurality of (three in the illustrated example) circumferential main grooves 2 (2a, 2b, 2c) extending in the tread circumferential direction, and a plurality of Between the circumferential main grooves 2 adjacent in the tread width direction of the circumferential main grooves 2, or by the circumferential main grooves 2 (2a, 2c) and the tread edge TE, a plurality (four in the illustrated example) ) land portions 3 (3a, 3b, 3c, 3d). In this example, one circumferential main groove 2b is positioned on the tire equatorial plane CL, and the other circumferential main grooves 2a and 2c are located on one side of the tread width direction with the tire equatorial plane CL as a boundary. Located in one half, the other half. In this example, two land portions 3 are arranged in each half portion in the tread width direction. As illustrated, the land portions 3b and 3c are land portions on the center side in the tread width direction, and the land portions 3a and 3d are land portions adjacent to the tread edge TE.

In the example shown in FIG. 1, the number of circumferential main grooves 2 is three, but may be two or four or more. Therefore, the number of land portions 3 can also be three or five or more. In this example, all the land portions are rib-like land portions 3, but at least one land portion may be a non-rib-like land portion, that is, a block-like land portion. The term “rib-like land portion” refers to a land portion that is not completely divided in the tread circumferential direction by widthwise grooves extending in the tread widthwise direction. Therefore, in this specification, even if the tread is completely divided in the tread circumferential direction by the width direction sipes, it is a "rib-like land portion".

The groove width (opening width (opening width measured perpendicularly to the extending direction of the groove in plan view)) of the circumferential main groove 2 is not particularly limited because it depends on the number of the circumferential main grooves 2. , for example 5 to 25 mm. Similarly, the groove depth (maximum depth) of the circumferential main groove 2 is not particularly limited, but can be, for example, 6 to 18 mm.

In the illustrated example, in a plan view of the tread surface 1, all of the circumferential main grooves 2 extend along the tread circumferential direction (without being inclined), but at least one circumferential main groove 2 extends along the tread circumference. It may extend at an angle of 5° or less with respect to the tread circumferential direction, for example. In the illustrated example, all of the circumferential main grooves 2 extend straight in the tread circumferential direction. Also good.

In the illustrated example, each land portion 3 has a plurality of widthwise grooves 4 extending in the tread widthwise direction. Specifically, in this example, the land portions 3a and 3d (rib-shaped in the illustrated example) adjacent to the tread edge TE extend inward in the tread width direction from the tread edge TE (rib-shaped in the illustrated example). Three width direction grooves 4 are provided in each of the land portions 3a and 3d within the illustrated range. In the land portions 3b and 3c (rib-shaped in the illustrated example) on the central side in the tread width direction, the land portions 3b and 3c extend outward in the tread width direction from the circumferential main groove 2b located on the tire equatorial plane CL (rib-shaped in the illustrated example). ) has three width direction grooves 4 each terminating in the land portions 3b and 3c within the illustrated range. The number of width direction grooves 4 can be set as appropriate. In the illustrated example, all the land portions 3 have the width direction grooves 4, but if the tread surface 1 has the width direction grooves 4, any land portion 3 has the width direction grooves 4. It is preferable that the land portions 3 (land portions 3 a and 3 d in the illustrated example) defined by the tread edge TE have the width direction grooves 4 .
Here, the groove width (opening width (opening width measured perpendicularly to the extending direction of the groove in plan view)) of the width direction groove 4 is not particularly limited because it depends on the number of width direction grooves 4. can be, for example, 1.0 to 1.5 mm. Similarly, the groove depth (maximum depth) of the width direction groove 4 is not particularly limited, but can be set to 4 to 18 mm, for example.
In the illustrated example, all width direction grooves 4 extend along the tread width direction (without being inclined), but at least one width direction groove 4 extends with an inclination with respect to the tread width direction. In this case, it preferably extends at an inclination angle of 45° or less with respect to the tread width direction, and preferably at an inclination angle of 30° or less. Moreover, in the illustrated example, the width direction grooves 4 all extend straight in the tread width direction, but at least one width direction groove 4 may have a bent portion.
Here, from the viewpoint of improving drainage performance, it is preferable that the width direction grooves 4 open at the tread edge TE or the circumferential direction main groove 2, for example, as in the illustrated example. On the other hand, in order to increase the rigidity of the land portion 3, the widthwise groove 4 may not open to either the tread edge TE or the circumferential main groove 2, and both ends may terminate within the land portion 3. can. Further, in the land portion 3 partitioned between two circumferential main grooves 2 adjacent in the tread width direction, the width direction groove 4 opens in which one of the two circumferential main grooves 2. It's okay to be there.

In the illustrated example, each land portion 3 has a plurality of widthwise grooves 4 and does not have a sipe. On the other hand, at least one or more land portions 3 may have sipes instead of or in addition to the widthwise grooves 4 . In addition, embodiment which the land part 3 has a sipe is mentioned later.

FIG. 2 is a cross-sectional view schematically showing an example of widthwise grooves. FIG. 2 is a tread circumferential cross-sectional view of width direction grooves extending along the tread width direction. FIG. 2 shows a state in which a tire is mounted on an applicable rim, filled with a specified internal pressure, and unloaded. In the example shown in FIG. 2, the width direction groove 4 has a constant groove width (the width measured parallel to the tread surface in a cross-sectional view) (equal to the opening width at the tread surface 1) on the tread surface 1 side. , a constant groove width portion 4a, and a widened portion 4b having a groove width larger than that of the tread surface 1 on the groove bottom side. In the illustrated example, the widened portion 4b is circular in cross section and has a maximum width W2 at the center in the tire radial direction. On the other hand, the widened portion 4b can have various shapes, such as an elliptical cross section (the length in the tire radial direction may be larger or smaller than the length in the tire circumferential direction), and a rectangular shape. etc.
In this example, the portion outside the widened portion 4b in the tire radial direction is the constant groove width portion 4a having a constant groove width, but this portion may be a portion having a variable groove width.

The groove width W1 of the constant groove width portion 4a is not particularly limited, but can be, for example, 1.0 to 1.5 mm. The maximum width W2 of the widened portion 4b is not particularly limited, but can be, for example, 1.2 to 6.0 mm. The groove depth h of the widthwise grooves is not particularly limited, but can be, for example, 4.0 to 18.0 mm. In addition, it is preferable that the groove width at the groove bottom of the width direction groove 4 is larger than 2.5W1.
An extension length h1 in the depth direction of the constant groove width portion 4a is not particularly limited, but can be, for example, 2 to 12 mm. The extension length h2 of the widened portion 4b in the depth direction is not particularly limited, but can be, for example, 1.5 to 8.0 mm.

Here, as shown in FIG. 2, the tire is mounted on the applicable rim, filled with a specified internal pressure, and in a no-load state, the opening width of the width direction groove 4 on the tread surface 1 (that is, in this example, the sipe When the width of the constant width portion 4a) is W1, the groove depth position on the outermost side in the tire radial direction at which the groove width of the widened portion 4 is 2.5W1 or more is defined as a reference depth position D.
At the reference depth position D, the rigidity usually begins to decrease as wear progresses.
In the tire of the present embodiment, the first tread, which is a groove wall surface layer portion that is defined by the widened portion 4b and covers at least a part of the widened portion 4b, in the tire radial direction region including at least the reference depth position D. The storage elastic modulus of the rubber G1 is greater than the storage elastic modulus of the second tread rubber G2 in the region surrounding the first tread rubber G1 (specifically, in the present embodiment, the storage elastic modulus of the first tread rubber G1 is The storage elastic modulus is at least 1.5 times the storage elastic modulus of the second tread rubber G2).
In the present embodiment, the tire radial region includes at least a region from the reference depth position D to the tire radial position where the widened portion 4b has the maximum width in the tire radial direction. 4b from the innermost end in the tire radial direction to the outermost end in the tire radial direction.
In this example, the first tread rubber G1 covers the widened portion 4b like a shell.
In this example, the first tread rubber G1 has an annular shape with a discontinuous portion in a cross section in the tread circumferential direction. When the widened portion 4b has an elliptical shape in the tread circumferential cross section, the first tread rubber G1 may be an elliptical ring having a discontinuity in the tread circumferential cross section. When the widened portion 4b has a rectangular cross section in the tread circumferential direction, the first tread rubber G1 may have a rectangular annular shape having a discontinuous portion in the tread circumferential cross section.
In this embodiment, the thickness t of the first tread rubber G1 in the direction normal to the contour line of the widened portion 4b is 1.0 mm or more in the tread circumferential cross-sectional view. In this example, the thickness t of the first tread rubber G1 is constant. On the other hand, the thickness t of the first tread rubber G1 may vary. In this case, for example, the thickness t of the first tread rubber G1 may gradually increase or decrease from the inner side to the outer side in the tire radial direction.
The first tread rubber G1 may be present in at least a part of the region in the extending direction of the width direction grooves 4 in plan view, but it may be present in the entire region in the direction of width direction grooves 4 in plan view. is preferably present over the
The effects of the pneumatic tire of this embodiment will be described below.

The pneumatic tire of this embodiment has a plurality of widthwise grooves 4 extending in the tread widthwise direction in the land portion 3, and the widthwise grooves 4 are located on the groove bottom side and have a groove width larger than that on the tread surface 1 side. It has a widened portion 4b. As a result, when the wear progresses, the widened portion 4b having a large groove width is exposed on the tread surface, so that the drainage performance when the wear progresses can be improved.
In the pneumatic tire of the present embodiment, the tire radial region including at least the reference depth position D is partitioned by the widened portion 4b, and the first The storage modulus of the tread rubber G1 is greater than the storage modulus of the second tread rubber G2 in the region surrounding the first tread rubber G1. As a result, when wear progresses, the rigidity of the reference depth position D and its vicinity can be increased, local wear can be suppressed, and uneven wear of the tire can be suppressed.
As described above, according to the pneumatic tire of the present embodiment, it is possible to improve the drainage performance while suppressing the occurrence of uneven wear when the wear progresses.

Furthermore, in the present embodiment, the tire radial region includes at least a region from the reference depth position D to the tire radial position where the widened portion 4b has the maximum width in the tire radial direction. WHEREIN: While the occurrence of uneven wear is further suppressed, drainage performance can be improved. In particular, in this example, the tire radial region is the entire area from the tire radially innermost end to the tire radially outermost end of the widened portion 4b, so that uneven wear is further suppressed when wear progresses. However, it is possible to improve the drainage performance.
In addition, in the present embodiment, the thickness t of the first tread rubber G1 in the direction normal to the contour line of the widened portion is 1.0 mm or more in a cross-sectional view in the tread circumferential direction. It is possible to improve drainage performance while further suppressing the occurrence of uneven wear.
Furthermore, in the present embodiment, the storage elastic modulus of the first tread rubber G1 is 1.5 times or more the storage elastic modulus of the second tread rubber G2. It is possible to improve the drainage property while suppressing it.

Next, other embodiments of the present invention will be described. FIG. 3 is a developed view schematically showing a tread pattern of a pneumatic tire according to another embodiment of the invention.
The tread pattern shown in FIG. 3 differs from the tread pattern shown in FIG. 1 in that each land portion 3 further has a plurality of widthwise sipes 5 extending in the tread widthwise direction. The circumferential main grooves 2, the land portions 3, and the widthwise grooves 4 in the other embodiment shown in FIG. 3 are the same as those in the embodiment shown in FIG. 1, including the illustrated configuration and modifications thereof. Therefore, detailed description will be omitted, and the width direction sipe 5 will be mainly described by way of example.

In the illustrated example, each land portion 3 has a plurality of widthwise sipes 5 extending in the tread widthwise direction. Specifically, in this example, in the land portions 3a and 3d adjacent to the tread edge TE, widths extending outward in the tread width direction from each of the circumferential main grooves 2a and 2c and terminating within the land portions 3a and 3d Three directional sipes 5 are provided within the illustrated range. Further, in the land portions 3b and 3c on the central side in the tread width direction, the widthwise sipes 5 extending inward in the tread width direction from the respective circumferential main grooves 2a and 2c and terminating within the land portions 3b and 3c are formed within the illustrated range. have three each. The number of width direction sipes 5 can be set as appropriate. In the illustrated example, all the land portions 3 have the widthwise sipes 5, but if the tread surface 1 has the widthwise sipes 5, any land portion 3 has the widthwise sipes 5. It is preferable that the land portions 3 (the land portions 3 a and 3 d in the illustrated example) defined by the tread edge TE have width direction sipes 5 .
Here, the sipe width (opening width (opening width measured perpendicularly to the extending direction of the widthwise sipes 5)) of the widthwise sipes 5 is not particularly limited because it depends on the number of the widthwise sipes 5. , for example 0.2 to 1.0 mm. Similarly, the sipe depth (maximum depth) of the width direction sipe 5 is not particularly limited, but can be, for example, 4.0 to 18.0 mm.
In the illustrated example, all width direction sipes 5 extend along the tread width direction (without being inclined), but at least one width direction sipe 5 extends with an inclination with respect to the tread width direction. In this case, it preferably extends at an inclination angle of 45° or less with respect to the tread width direction, and preferably at an inclination angle of 30° or less. In the illustrated example, all of the widthwise sipes 5 extend straight in the tread width direction, but at least one widthwise sipe 5 may have a bent portion.
Here, from the viewpoint of improving drainage performance, it is preferable that the width direction sipes 5 open at the tread edge TE or the circumferential direction main groove 2 as in the illustrated example. On the other hand, in order to increase the rigidity of the land portion 3, the width direction sipe 5 may not open to either the tread edge TE or the circumferential main groove 2, and both ends may terminate within the land portion 3. can. In the land portion 3 defined between the two circumferential main grooves 2 adjacent in the tread width direction, the widthwise sipe 5 opens in either of the two circumferential main grooves 2. It's okay to be there.

Here, in the illustrated example, the widthwise grooves 4 and the widthwise sipes 5 are alternately arranged when viewed in the tread circumferential direction. Thereby, the balance of the rigidity of the land part 3 can be optimized more. On the other hand, when viewed in the tread circumferential direction, there may be a portion where two or more width direction grooves 4 are continuously arranged between two width direction sipes 5 adjacent in the tread circumferential direction, Further, there may be a portion where two or more widthwise sipes 5 are continuously arranged between two widthwise grooves 4 adjacent to each other in the red circumferential direction.
In the illustrated example, the widthwise grooves 4 and the widthwise sipes 5 both terminate at the center of the land portion 3 in the tread widthwise direction. They may have overlapping portions when projected, or may be arranged so as not to overlap.

FIG. 4 is a cross-sectional view schematically showing an example of width direction sipes. FIG. 4 is a tread circumferential cross-sectional view of width direction sipes extending along the tread width direction. FIG. 4 shows a state in which the tire is mounted on an applicable rim, filled with a specified internal pressure, and unloaded. In the example shown in FIG. 4, the width direction sipe 5 has a constant sipe width (the width measured parallel to the tread surface 1 in a cross-sectional view) (equal to the opening width at the tread surface 1) on the tread surface 1 side. It has a constant sipe width portion 5a, and has a widened portion 5b on the groove bottom side, the groove width of which is larger than that on the tread surface 1 side. In the illustrated example, the widened portion 5b is circular in cross section and has a maximum width W4 at the center in the tire radial direction. On the other hand, the widened portion 5b may have various shapes, such as an elliptical cross section (the length in the tire radial direction may be larger or smaller than the length in the tire circumferential direction), a rectangular shape, and the like. etc.
In this example, the portion outside the widened portion 5b in the tire radial direction is the constant groove width portion 5a having a constant groove width, but this portion may be a portion having a variable groove width.

The sipe width W3 of the constant sipe width portion 5a is not particularly limited, but can be, for example, 0.2 to 1.0 mm. The maximum width W4 of the widened portion 5b is not particularly limited, but can be, for example, 1.2 to 6.0 mm. The sipe depth g of the width direction sipe 5 is not particularly limited, but can be set to 4.0 to 18.0 mm, for example. The sipe width at the sipe bottom of the width direction sipe 5 is preferably larger than 2.5W3.
The extension length g1 in the depth direction of the constant sipe width portion 5a is not particularly limited, but can be, for example, 2 to 12 mm. The extension length g2 of the widened portion 5b in the depth direction is not particularly limited, but can be, for example, 1.5 to 8.0 mm.

Here, as shown in FIG. 4, when the tire is mounted on the applicable rim, filled with a specified internal pressure, and in a no-load state, when the opening width of the width direction sipe 5 at the tread surface 1 is W3, the widened portion The outermost groove depth position in the tire radial direction where the groove width of 5b is 2.5W3 or more is defined as a reference depth position D'.
At the reference depth position D', the rigidity usually starts to decrease when wear progresses.
From the viewpoint of manufacturability, it is preferable that the reference depth position D and the reference depth position D' have the same depth. It can be larger or smaller.
In addition, in the tire of the present embodiment, in the tire radial direction region including at least the reference depth position D′, the first groove wall surface portion defined by the widened portion 5b and covering at least a part of the widened portion 5b The storage elastic modulus of the tread rubber G3 is greater than the storage elastic modulus of the second tread rubber G4 in the region surrounding the first tread rubber G3 (specifically, in this embodiment, the storage elastic modulus of the first tread rubber G3 is 1.5 times or more that of the second tread rubber G4).
In the present embodiment, the tire radial region includes at least a region from the reference depth position D' to the tire radial position where the widened portion 5b has the maximum width in the tire radial direction. It is the entire region from the tire radial direction innermost end to the tire radial direction outermost end of the portion 5b.
In this example, the first tread rubber G3 covers the widened portion 5b like a shell.
In this example, the first tread rubber G3 has an annular shape with a discontinuous portion in a cross section in the tread circumferential direction. When the widened portion 5b has an elliptical shape in the tread circumferential cross section, the first tread rubber G3 can be an elliptical ring having a discontinuous portion in the tread circumferential cross section. When the widened portion 5b has a rectangular cross section in the tread circumferential direction, the first tread rubber G3 may have a rectangular annular shape having a discontinuous portion in the tread circumferential cross section.
In this embodiment, the thickness t of the first tread rubber G1 in the direction normal to the contour line of the widened portion 5b is 1.0 mm or more in the tread circumferential cross-sectional view. In this example, the thickness t of the first tread rubber G1 is constant. On the other hand, the thickness t of the first tread rubber G1 may vary. In this case, for example, the thickness t of the first tread rubber G1 may gradually increase or decrease from the inner side to the outer side in the tire radial direction.
Regarding the tread rubbers that partition the widthwise sipes 5, the ratio of the storage elastic modulus of the first tread rubber G3 to the storage elastic modulus of the second tread rubber G4 is is preferably the same as the ratio of the storage modulus of the first tread rubber to the storage modulus of the second tread rubber G2 for the tread rubbers defining the Small is fine.
The first tread rubber G3 may be present in at least a part of the region in the extending direction of the widthwise sipes 5 in plan view, but the entire area in the extending direction of the widthwise sipes 5 in plan view. is preferably present over the
The effects of the pneumatic tire of another embodiment shown in FIGS. 3 and 4 will be described below.

According to the pneumatic tire of another embodiment shown in FIGS. Similar effects can be obtained.
In addition, the pneumatic tire of the present embodiment shown in FIGS. 3 and 4 has a plurality of widthwise sipes 5 extending in the tread widthwise direction in the land portion 3, and the widthwise sipes 5 are located on the bottom side of the sipe. In addition, it has a widened portion 5b whose sipe width is larger than that on the tread surface 1 side. As a result, the widened portion 5b having a large sipe width is exposed on the tread surface when wear progresses, thereby improving drainage performance when wear progresses.
In the pneumatic tire of the embodiment shown in FIGS. 3 and 4, the tire radial region including at least the reference depth position D' is defined by the widened portion 5b, and at least a portion of the widened portion 5b is covered. The storage elastic modulus of the first tread rubber G3, which is the groove wall surface layer, is larger than the storage elastic modulus of the second tread rubber G4 in the region surrounding the first tread rubber G3. As a result, when wear progresses, the rigidity of the reference depth position D' and its vicinity can be increased, local wear can be suppressed, and uneven wear of the tire can be suppressed.
As described above, according to the pneumatic tire of the other embodiment shown in FIGS. 3 and 4, it is possible to further suppress the occurrence of uneven wear and improve the drainage performance when the wear progresses. can.

Furthermore, in the present embodiment, the tire radial direction region includes at least a region from the reference depth position D′ to the tire radial position where the widened portion 5b has the maximum width in the tire radial direction. Occasionally, it is possible to improve drainage while further suppressing the occurrence of uneven wear. In particular, in this example, the tire radial region is the entire area from the tire radially innermost end to the tire radially outermost end of the widened portion 5b, so that uneven wear is further suppressed when wear progresses. However, it is possible to improve the drainage performance.
In addition, in the present embodiment, the thickness t of the first tread rubber G3 in the direction normal to the contour line of the widened portion is 1.0 mm or more in the tread circumferential cross-sectional view. It is possible to improve drainage performance while further suppressing the occurrence of uneven wear.
Furthermore, in the present embodiment, the storage elastic modulus of the first tread rubber G3 is 1.5 times or more the storage elastic modulus of the second tread rubber G4. It is possible to improve the drainage property while suppressing it.

Another embodiment of the present invention will now be described. FIG. 5 is a developed view schematically showing a tread pattern of a pneumatic tire according to another embodiment of the invention.
The tread pattern shown in FIG. 5 differs from the tread pattern shown in FIG. 1 in that each land portion 3 further has a plurality of circumferential sipes 6 extending in the tread circumferential direction. The circumferential main grooves 2, the land portions 3, and the widthwise grooves 4 in another embodiment shown in FIG. 5 are the same as those of the embodiment shown in FIG. Therefore, detailed description will be omitted, and the circumferential sipes 6 will mainly be illustrated and described below.

In the illustrated example, each land portion 3 has a plurality of circumferential sipes 6 extending in the tread circumferential direction. Specifically, in this example, in each rib-like land portion 3 adjacent to the tread edge TE, four circumferential sipes 6 extending in the tread circumferential direction and having both ends terminated within the land portion 3 are formed within the illustrated range. I have each book. The number of circumferential sipes 6 can be set as appropriate. In this example, both ends of the circumferential sipe 6 terminate within the rib-shaped land portion 3, but the circumferential sipe 6 may be a single circumferential sipe 6 extending continuously in the tread circumferential direction. can. In the illustrated example, all the land portions 3 have the circumferential sipes 6, but if the tread surface 1 has the circumferential sipes 6, any land portion 3 has the circumferential sipes 6. It is preferable that the land portions 3 (the land portions 3 a and 3 d in the illustrated example) defined by the tread edge TE have circumferential sipes 6 .
Here, the sipe width (opening width (opening width measured perpendicularly to the extending direction of the circumferential sipes 6)) of the circumferential sipes 6 is not particularly limited because it depends on the number of the circumferential sipes 6. , for example 0.2 to 1.5 mm. Similarly, the sipe depth (maximum depth) of the circumferential sipe 6 is not particularly limited, but can be, for example, 4.0 to 18.0 mm.
In the illustrated example, all circumferential sipes 6 extend along the tread circumferential direction (without being inclined), but at least one circumferential sipe 6 extends obliquely with respect to the tread circumferential direction. In this case, it preferably extends at an inclination angle of 25° or less with respect to the tread circumferential direction, and preferably at an inclination angle of 10° or less. In the illustrated example, all of the circumferential sipes 6 extend straight in the tread circumferential direction, but at least one circumferential sipe 6 may have a bent portion.

Here, in the illustrated example, in each land portion 3, the width direction grooves 4 and the circumferential direction sipes 6 are arranged so as not to overlap when projected in the tread width direction, but are arranged so as to have overlapping portions. can be

FIG. 6 is a cross-sectional view schematically showing an example of a circumferential sipe. FIG. 6 is a cross-sectional view in the tread width direction of circumferential sipes extending along the tread circumferential direction. FIG. 6 shows a state in which a tire is mounted on an applicable rim, filled with a specified internal pressure, and no load is applied. In the example shown in FIG. 6, the circumferential sipe 6 has a constant sipe width (the width measured parallel to the tread surface 1 in a cross-sectional view) (equal to the opening width at the tread surface 1) on the tread surface 1 side. It has a constant sipe width portion 6a, and has a widened portion 6b on the groove bottom side, the groove width of which is larger than that on the tread surface 1 side. In the illustrated example, the widened portion 6b is circular in cross section and has a maximum width W6 at the center in the tire radial direction. On the other hand, the widened portion 6b can have various shapes, such as an elliptical cross-section (the length in the tire radial direction may be larger or smaller than the length in the tire width direction), and a rectangular shape. etc.
In this example, the portion from the tire radial direction outer side of the widened portion 6b is the constant groove width portion 6a having a constant groove width, but this portion may be a portion having a variable groove width.

The width W5 of the constant sipe width portion 6a is not particularly limited, but can be, for example, 0.2 to 1.5 mm. The maximum width W6 of the widened portion 6b is not particularly limited, but can be, for example, 1.2 to 6.0 mm. The depth g' of the circumferential sipe 5 is not particularly limited, but can be, for example, 4.0 to 18.0 mm. The sipe width at the sipe bottom of the circumferential sipe 6 is preferably larger than 2.5W5.
The extension length g1' of the constant sipe width portion 6a in the depth direction is not particularly limited, but can be, for example, 2.0 to 12 mm. The extension length g2' of the widened portion 6b in the depth direction is not particularly limited, but can be, for example, 1.5 to 8.0 mm.

Here, as shown in FIG. 6, when the tire is mounted on the applicable rim, filled with a specified internal pressure, and in a no-load state, when the opening width of the circumferential sipe 6 at the tread surface 1 is W5, the widened portion The outermost groove depth position in the tire radial direction where the groove width of 6b is 2.5W5 or more is defined as a reference depth position D''.
At the reference depth position D'', the rigidity usually starts to decrease when wear progresses.
From the viewpoint of manufacturability, it is preferable that the reference depth position D and the reference depth position D'' have the same depth. It can be larger or smaller than ''.
In the tire of the present embodiment, in the tire radial direction region including at least the reference depth position D'', the first is larger than the storage modulus of the second tread rubber G6 in the region surrounding the first tread rubber G5 (specifically, in this embodiment, the first tread rubber The storage modulus of G5 is at least 1.5 times the storage modulus of the second tread rubber G6).
In the present embodiment, the tire radial region includes at least a region from the reference depth position D'' to the tire radial position where the widened portion 6b has the maximum width in the tire radial direction. It is the entire region from the tire radial direction innermost end of the widened portion 6b to the tire radial direction outermost end.
In this example, the first tread rubber G5 covers the widened portion 5b like a shell.
In this example, the first tread rubber G5 has an annular shape with a discontinuous portion in the cross section in the tread width direction. When the widened portion 6b has an elliptical cross section in the tread width direction, the first tread rubber G5 may have an elliptical ring shape having a discontinuity in the tread width direction cross section. When the widened portion 6b has a rectangular cross section in the tread width direction, the first tread rubber G5 may have a rectangular annular shape having a discontinuous portion in the tread width direction cross section.
Further, in the present embodiment, the thickness t of the first tread rubber G5 in the direction normal to the contour line of the widened portion 6b is 1.0 mm or more in a cross-sectional view in the tread width direction. In this example, the thickness t of the first tread rubber G5 is constant. On the other hand, the thickness t of the first tread rubber G5 may vary. In this case, for example, the thickness t of the first tread rubber G5 may gradually increase or decrease from the inner side to the outer side in the tire radial direction.
Regarding the tread rubber that partitions the circumferential sipe 6, the ratio of the storage elastic modulus of the first tread rubber G5 to the storage elastic modulus of the second tread rubber G6 is the width direction groove 4 from the viewpoint of manufacturability. is preferably the same as the ratio of the storage modulus of the first tread rubber G1 to the storage modulus of the second tread rubber G2 for the tread rubbers defining the can be smaller.
The first tread rubber G5 may exist in at least a part of the region in the extending direction of the circumferential sipe 6 in plan view. is preferably present over the
The effects of the pneumatic tire of another embodiment shown in FIGS. 5 and 6 will be described below.

According to the pneumatic tire of another embodiment shown in FIGS. Similar effects can be obtained.
In addition, the pneumatic tire of this embodiment shown in FIGS. 5 and 6 has one or more circumferential sipes 6 extending in the tread circumferential direction in the land portion 3, and the circumferential sipes 6 have sipe bottoms. The side has a widened portion 6b whose sipe width is larger than that of the tread surface 1 side. As a result, the widened portion 6b having a large sipe width is exposed on the tread surface when wear progresses, thereby improving drainage performance when wear progresses.
In the pneumatic tire of the embodiment shown in FIGS. 5 and 6, the tire radial region including at least the reference depth position D'' is defined by the widened portion 6b, and at least part of the widened portion 6b is The storage elastic modulus of the first tread rubber G5, which is the covering groove wall surface layer portion, is greater than the storage elastic modulus of the second tread rubber G6 in the region surrounding the first tread rubber G5. As a result, when wear progresses, the rigidity of the reference depth position D'' and its vicinity can be increased, local wear can be suppressed, and uneven wear of the tire can be suppressed.
As described above, according to the pneumatic tire of the other embodiment shown in FIGS. 5 and 6, it is possible to further suppress the occurrence of uneven wear and improve the drainage performance when the wear progresses. can.

Furthermore, in the present embodiment, the tire radial direction region includes at least a region from the reference depth position D'' to the tire radial position where the widened portion 6b has the maximum width in the tire radial direction. At the time of progress, it is possible to improve drainage while further suppressing the occurrence of uneven wear. In particular, in this example, since the tire radial region is the entire area from the tire radially innermost end to the tire radially outermost end of the widened portion 6b, the occurrence of uneven wear is further suppressed when wear progresses. However, it is possible to improve the drainage performance.
Further, in the present embodiment, the thickness t of the first tread rubber G5 in the direction normal to the contour line of the widened portion is 1.0 mm or more in cross-sectional view in the tread width direction. It is possible to improve drainage performance while further suppressing the occurrence of uneven wear.
Furthermore, in the present embodiment, the storage elastic modulus of the first tread rubber G5 is 1.5 times or more the storage elastic modulus of the second tread rubber G6. It is possible to improve the drainage property while suppressing it.

In each of the above examples, the tire radial region preferably includes at least a region from the reference depth position to the tire radial position where the widened portion has the maximum width in the tire radial direction. This is because, when the wear progresses, it is possible to further suppress the occurrence of uneven wear and improve the drainage performance. Further, it is more preferable that the tire radial region is the entire region from the radially innermost end of the widened portion to the radially outermost end of the tire. This is because, when the wear progresses, it is possible to further suppress the occurrence of uneven wear and improve the drainage performance.

Further, in each of the above examples, the first tread rubber in a cross-sectional view (cross-sectional view in the tread circumferential direction in the examples of FIGS. 1 to 4, and cross-sectional view in the tread width direction in the examples of FIGS. 5 and 6) It is preferable that the thickness t in the normal direction of the outline of the portion is 1.0 mm or more. This is because, when the wear is in the above range, it is possible to further suppress the occurrence of uneven wear and to improve the drainage performance when the wear progresses. For the same reason, the thickness t is more preferably 1.5 mm or more. On the other hand, it is preferable that the thickness t is 2.0 mm or less in order to prevent the rigidity of the land portion from becoming too high and the riding comfort from deteriorating.

Moreover, the storage elastic modulus of the first tread rubber is preferably 1.5 times or more the storage elastic modulus of the second tread rubber. This is because, when the wear progresses, it is possible to improve drainage performance while particularly suppressing the occurrence of uneven wear. For the same reason, the storage elastic modulus of the first tread rubber is more preferably 1.8 times or more the storage elastic modulus of the second tread rubber. On the other hand, from the viewpoint of preventing the rigidity step from becoming too large, the storage elastic modulus of the first tread rubber is preferably 3.5 times or less that of the second tread rubber.

In addition, at least the land portion defined by the tread edge may have a width direction groove having a widened portion (using the first tread rubber that makes the storage elastic modulus relatively higher than that of the second tread rubber). preferable. This is because, particularly at least in the land portion defined by the tread edge, it is possible to improve the drainage performance while suppressing the occurrence of uneven wear when the wear progresses.
In addition, at least the land portion partitioned by the tread edge may have a widthwise sipe having a widened portion (using the first tread rubber that makes the storage elastic modulus relatively higher than that of the second tread rubber). preferable. This is because, particularly at least in the land portion defined by the tread edge, it is possible to improve the drainage performance while suppressing the occurrence of uneven wear when the wear progresses.
In addition, at least the land portion partitioned by the tread edge may have a circumferential sipe having a widened portion (using the first tread rubber that makes the storage elastic modulus relatively higher than that of the second tread rubber). preferable. This is because, particularly at least in the land portion defined by the tread edge, it is possible to improve the drainage performance while suppressing the occurrence of uneven wear when the wear progresses.
These configurations are particularly suitable for tires with a relatively large amount of wear in the land portions defined by the tread edges.

The width direction grooves can be produced by using a mold having a corresponding shape, for example. Also, the width direction sipe and the circumferential sipe can be produced using blades having corresponding shapes, for example. Also, in order to cover a part of the widened portion with a tread rubber with a high storage modulus, for example, only the surface of the tire before vulcanization is covered with a tread rubber with a high storage modulus, and then a mold shape corresponding to the vulcanization is applied. can be produced by drawing the tread rubber in the tire depth direction when the tread rubber penetrates the tread rubber.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments. For example, in another embodiment shown in FIGS. 3 and 4, the widthwise groove 4 has the shape shown in FIG. 2, and the widthwise sipe 5 has the shape shown in FIG. However, for example, the widthwise groove 4 may have a U-shaped cross section and a V-shaped cross section, and the widthwise sipe 5 may have the shape shown in FIG. Similarly, in another embodiment shown in FIGS. 5 and 6, the width direction groove 4 has the shape shown in FIG. 2 and the circumferential sipe 6 has the shape shown in FIG. However, for example, the width direction groove 4 may be a groove having a U-shaped cross section and a V-shaped cross section, and the circumferential sipe 6 may have the shape shown in FIG.
Further, for example, in the embodiments shown in FIGS. 1 to 6, the land portions have the width direction grooves, but the land portions do not have the width direction grooves, and any land portion has the width direction sipe and the width direction groove. / Or it can be configured to have only circumferential sipes. In that case, the arrangement, sipe width, sipe depth, shape, etc. of the width direction sipes and/or the circumferential sipes can be the same as those described in the embodiment shown in FIGS. That is, the land portion has a plurality of widthwise sipes extending in the tread widthwise direction, and the widthwise sipes have, on the sipe bottom side, a widened portion where the sipe width is larger than that on the tread surface side, and at least the reference depth In the tire radial region including the position, the storage elastic modulus of the first tread rubber, which is the groove wall surface layer portion that is partitioned by the widened portion and covers at least a part of the widened portion, is higher than the circumference of the first tread rubber. The land portion has one or more circumferential sipes extending in the tread circumferential direction, and the circumferential sipes have a sipe width on the sipe bottom side. has a widened portion that is larger than the tread surface side, and is a groove wall surface layer portion that is partitioned by the widened portion in a tire radial direction region including at least the reference depth position and covers at least a part of the widened portion. The storage modulus of the tread rubber may be greater than the storage modulus of the second tread rubber in the region surrounding the first tread rubber.
Furthermore, unlike the configurations shown in FIGS. 1 to 6, it is also possible to have a configuration with or without width direction grooves and having both width direction sipes and circumferential direction sipes. In this case, the width direction sipe and the circumferential sipe may or may not intersect. Then, for both or only one of the width direction sipe and the circumferential sipe, the sipe bottom side has a widened portion where the sipe width is larger than the tread surface side, and in the tire radial region including at least the reference depth position, The storage elastic modulus of the first tread rubber, which is the groove wall surface layer portion that is partitioned by the widened portion and covers at least a part of the widened portion, is higher than the storage modulus of the second tread rubber in the region around the first tread rubber. It can be configured to be greater than the elastic modulus.
As described above, at least one of the widthwise grooves, the widthwise sipes, and the circumferential sipes may be provided on the tread surface. Then, in at least one of the width direction groove, the width direction sipe, and the circumferential direction sipe, a widened portion is formed on the groove bottom side (sipe bottom side) so that the groove width (sipe width) is larger than that on the tread surface side. The storage elastic modulus of the first tread rubber, which is a groove wall surface layer portion that is defined by the widened portion and covers at least a part of the widened portion, in the tire radial region including at least the reference depth position is The storage elastic modulus of the second tread rubber in the region surrounding the first tread rubber may be larger than that of the second tread rubber.
From the viewpoint of manufacturability, it is preferable that the reference depth position D, the reference depth position D', and the reference depth position D'' have the same depth. The size relationship among the reference depth position D, the reference depth position D', and the reference depth position D'' does not matter.
From the viewpoint of manufacturability, the ratio of the storage elastic modulus of the first tread rubber to the storage elastic modulus of the second tread rubber with respect to the tread rubbers that partition the width direction grooves, the width direction sipes, and the circumferential direction sipes. are preferably the same, but may be different, and in that case the size relationship does not matter.
Moreover, when the width direction groove, the width direction sipe, and the circumferential direction sipe have corners, at least one corner may be chamfered or the like to form a rounded portion.
The pneumatic tire of the present invention is particularly suitable for use as a tire for passenger cars and a tire for heavy loads (particularly a tire for trucks and buses).

1: tread tread,
2: Circumferential main groove,
3: Rikubu,
4: width direction groove, 4a: constant groove width portion, 4b: widened portion, 4b1: first widened portion,
4b2: second widened portion,
5: width direction sipe, 5a: constant sipe width portion, 5b: widening portion,
6: circumferential sipe, 6a: constant sipe width portion, 6b: widened portion,
G1, G3, G5: first tread rubber,
G2, G4, G6: second tread rubber,
CL: tire equatorial plane,
TE: Tread edge

Claims (13)

In the tread surface, a plurality of circumferential main grooves extending in the tread circumferential direction, and between the circumferential main grooves adjacent in the tread width direction among the plurality of circumferential main grooves, or between the circumferential main grooves A pneumatic tire having a plurality of land portions partitioned by tread edges,
The land portion has a plurality of width direction grooves extending in the tread width direction,
The width direction groove has, on the groove bottom side, a widened portion in which the groove width is larger than that on the tread surface side,
When the pneumatic tire is mounted on an applicable rim, filled with a specified internal pressure, and in an unloaded state, the groove width of the widened portion of the width direction groove is 2 times the width of the opening of the width direction groove on the tread surface. When the outermost groove depth in the tire radial direction, which is 5 times or more, is taken as the reference depth position,
In a tire radial direction region including at least the reference depth position, the storage elastic modulus of the first tread rubber, which is a groove wall surface layer portion that is partitioned by the widened portion and covers at least a part of the widened portion, is equal to the first greater than the storage modulus of the second tread rubber in the region surrounding the tread rubber of the second pneumatic tire. In the tread surface, a plurality of circumferential main grooves extending in the tread circumferential direction, and between the circumferential main grooves adjacent in the tread width direction among the plurality of circumferential main grooves, or between the circumferential main grooves A pneumatic tire having a plurality of land portions partitioned by tread edges,
The land portion has a plurality of width direction sipes extending in the tread width direction,
The width direction sipe has, on the sipe bottom side, a widened portion in which the sipe width is larger than the tread tread surface side,
When the pneumatic tire is mounted on an applicable rim, filled with a specified internal pressure, and in a no-load state, the sipe width of the widened portion of the widthwise sipe is 2 times the opening width of the widthwise sipe at the tread surface. When the outermost sipe depth in the tire radial direction, which is 5 times or more, is taken as the reference depth position,
In a tire radial direction region including at least the reference depth position, the storage elastic modulus of the first tread rubber, which is a groove wall surface layer portion that is partitioned by the widened portion and covers at least a part of the widened portion, is equal to the first greater than the storage modulus of the second tread rubber in the region surrounding the tread rubber of the second pneumatic tire. In the tread surface, a plurality of circumferential main grooves extending in the tread circumferential direction, and between the circumferential main grooves adjacent in the tread width direction among the plurality of circumferential main grooves, or between the circumferential main grooves A pneumatic tire having a plurality of land portions partitioned by tread edges,
The land portion has one or more circumferential sipes extending in the tread circumferential direction,
The circumferential sipe has, on the sipe bottom side, a widened portion where the sipe width is larger than the tread surface side,
When the pneumatic tire is mounted on an applicable rim, filled with a specified internal pressure, and in a no-load state, the sipe width of the widened portion of the circumferential sipe is 2 times the opening width of the tread surface of the circumferential sipe. When the outermost sipe depth in the tire radial direction, which is 5 times or more, is taken as the reference depth position,
In a tire radial direction region including at least the reference depth position, the storage elastic modulus of the first tread rubber, which is a groove wall surface layer portion that is partitioned by the widened portion and covers at least a part of the widened portion, is equal to the first greater than the storage modulus of the second tread rubber in the region surrounding the tread rubber of the second pneumatic tire. The width at the reference depth position is not the maximum width,
According to any one of claims 1 to 3, wherein the tire radial region includes at least a region from the reference depth position to the tire radial position where the widened portion has the maximum width in the tire radial direction. Pneumatic tires as described. The pneumatic tire according to any one of claims 1 to 4, wherein the tire radial region is the entire area from the radially innermost end of the widened portion to the tire radially outermost end. 2. The thickness t of the first tread rubber in the direction normal to the contour line of the widened portion of the widthwise groove in the tread circumferential cross section is 1.0 mm or more. 6. A pneumatic tire according to claim 4 or 5 depending on. 3. The thickness t of the first tread rubber in the direction normal to the contour line of the widened portion of the widthwise sipe in the tread circumferential cross section is 1.0 mm or more. 6. A pneumatic tire according to claim 4 or 5 depending on. 4. The thickness t of the first tread rubber in the direction normal to the contour line of the widened portion of the circumferential sipe in a cross-sectional view in the tread width direction is 1.0 mm or more. 6. A pneumatic tire according to claim 4 or 5 depending on. The pneumatic tire according to any one of claims 1 to 8, wherein the storage elastic modulus of the first tread rubber is 1.5 times or more the storage elastic modulus of the second tread rubber. The pneumatic tire according to any one of claims 1 to 9, wherein the storage elastic modulus of the first tread rubber is 1.8 times or more the storage elastic modulus of the second tread rubber. Claim 1 or any one of Claims 4 to 6, 9, and 10 depending on Claim 1, wherein the land portion defined by at least the tread edge has the widthwise groove having the widened portion. pneumatic tires. Claim 2 or any one of Claims 4, 5, 7, 9, and 10 depending on Claim 2, wherein the land portion defined by at least the tread edge has the widthwise sipe having the widened portion. The pneumatic tire described in . Claim 3 or any one of Claims 4, 5, 8 to 10 depending on Claim 3, wherein the land portion defined by at least the tread edge has the circumferential sipe having the widened portion. pneumatic tires.

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